NEW YORK (NewsNation Now) — It’s being called the biggest medical breakthrough the world has seen in the last hundred years — and it will come not a moment too soon.

Drugmaker Pfizer says it has developed a vaccine that shows 90% effectiveness against COVID-19, with no serious safety concerns so far. The company believes it can have millions of doses available by the end of the year with more widespread availability by Q3 of 2021.

It took a big gamble — paying to fast-track a new product with technology never used in the history of human vaccination — but the upside promises to be enormous.

With German partner BioNTech, the Pfizer team used messenger RNA, or mRNA, to produce an immune response, compressing a 5-year process into the past 10 months. The company’s CEO called Monday a great day for science and humanity.

“This means we are one step closer to potentially providing people around the world with a much-needed breakthrough to help bring an end to this global pandemic,” said Dr. Albert Bourla. “This is a first but critical step in our work to deliver a safe and effective vaccine.”

The Food and Drug Administration says study participants need to be monitored for two months for side effects and the vaccine study results need to be peer-reviewed, but at this very early stage, the vaccine looks extremely promising with no safety concerns identified so far.

Mike Hammonds of Tampa, Florida was one of the nearly 44,000 study participants who received either the vaccine or a placebo. Mike’s convinced he got the real thing, as he suffered a few hours of ill effects, but tells NewsNation affiliate WFLA he wanted to participate, “To help out with putting an end to the pandemic.”

University Hospitals in Cleveland was one of the clinical trial sites. Its Vice president of Research, Dr. Grace McComsey, is extremely optimistic.

“Literally, we are seeing light at the end of the tunnel,” Dr. McComsey said. “We just have to get through this month, make sure there are no safety concerns, and that the FDA approves the emergency use authorization.”

Although the vaccine’s development was dramatically accelerated, the trial followed protocol — moving at what a layman might consider a painfully slow pace. When phases 1 and 2 showed promise over the summer, there was no rush to release the vaccine, even as the US saw another rise in infections. Instead, the team waited for critical data from phase 3.

In Charlotte, North Carolina, George Washington III was elated when he heard the news. He survived a bought with COVID-19 but lost his father to it.

“I can’t be happier to hear that there’s a possibility that no one else has to go through what my family went through,” he said Monday.

Pfizer plans to work as quickly as possible to make the vaccine widely available once approved. In the meantime, medical experts are reminding people to stick to the basics: social-distancing, wearing masks, and washing their hands.